Role of Amino Acids and Vitamins in Nutrition of Mesophilic Methanococcus spp
AUTOR(ES)
Whitman, William B.
RESUMO
In this study we found that autotrophic methanococci similar to Methanococcus maripaludis obtained up to 57% of their cellular carbon from exogenous amino acids. About 85% of the incorporation was into protein. Primarily nonpolar and basic amino acids and glycine were incorporated; only small amounts of acidic and some polar amino acids were taken up. An additional 10% of the incorporation was into the nucleic acid fraction. Because little 14CO2 was formed from the 14C-amino acids, little metabolism of the amino acids occurred. Therefore the growth stimulation by amino acids was probably due to the sparing of anabolic energy requirements. Of the amino acids incorporated, only alanine was also a sole nitrogen source for these methanococci. In contrast, Methanococcus vannielii and “Methanococcus aeolicus” are autotrophic methanococci which did not incorporate amino acids and did not utilize alanine as a sole nitrogen source. Although glutamine served as a sole nitrogen source for the autotrophic methanococci and Methanococcus voltae, a heterotrophic methanococcus, growth was due to chemical deamination in the medium. M. voltae requires leucine and isoleucine for growth. However, these amino acids were not significant nitrogen sources, and alanine was not a sole nitrogen source for the growth of M. voltae. The branched-chain amino acids were not extensively metabolized by M. voltae. Pantoyl lactone and pantoic acid were readily incorporated by M. voltae. The intact vitamin pantothenate was neither stimulatory to growth nor incorporated. In conclusion, although amino acids and vitamins are nutritionally important to both autotrophic and heterotrophic methanococci, generally they are not subject to extensive catabolism.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=204115Documentos Relacionados
- Abnormal concentrations of B vitamins and amino acids in plasma and B vitamins in bile of rabbits with aflatoxicosis.
- Pathways of biosynthesis of aromatic amino acids and vitamins and their control in microorganisms.
- Assay of Vitamins and Amino Acids With Cultured Tissue Cells and Antimetabolites
- Availability of Essential Vitamins and Amino Acids for Lactobacillus plantarum in Cucumber Fermentations1
- AMINO ACIDS IN THE NUTRITION OF EXCISED TOMATO ROOTS